Lifting jack



May 18, 1948, F. P. HALLOR v LIFTING JACK Filed July 8, 194s ammo kwPatented May 18, 1948 Marianna,remain.

' Application July 8, 1946,;Serial No,.;.681,893

This invention relates to lifting-jacks employing a pair of pawls usedfor both load lifting and load'lowering purposes, j V

An important objectof the invention is to provide means which, when a"load on the jack is being let down, the pawls may be individuallycontrolled in a wholly positivemanner to thereby'prevent falling of suchload as often results inthe use of such jacks; 7 7

Further, an object is to provide means at each pawl'so that the jackmaybe operated in a positive 'and'saie manner without the necessity ofthe operator adjusting orhaving to touch either pawl to make sure ofsafe lowering operations. V "j Still another object is to automaticallyand separately control'each of' the two pawls of a jaclg'looking to safelowering of a load, so that the operator need devote his entire time andattention to the operating hand-lever only and the efiects upon the'loadbeing handled.

Other objects and'advantages will appear herein as the descriptionproceeds aided by theappended drawing forming part hereof, and whereinFigure '1' is -al'sideelevation of apart of a common formof j'ackrwhiichincludes therein the partsoflmy invention' 7 Y i v V Figure 2 is a plan"of the jack according to my invention, said jack being shownin'horizonta'l section on line 2, 2 of Figure 1. V

Figure 3 is a side elevation of the same wherein the parts of' theinvention are shown in dif-" ferent positions from those shownin'Figure 1. V Figure :4 is a transverse section of a forked portion ofth han'd-lever'o'f the jack and a manner or mountingth'ereon a swingablemeni-p ber shown in the foregoingfig'ures;

Figure 5 is a longitudinal sectionof aswingable memberi shown 'in Figure 4'," produced in'a larger- 09,115:] g t a Figure 6 isa detail inelevation of pa'rtsshown' in theiioregoing f gures, and .7 I I Figure '7is: n enlarged plan of a member shown in the earlierfigu res', togetherwith a rod portion to engage therein.

The mechanism of the I, "invention is adaptable to certain forms ofjacks of. the type named herein; While also adapted to be mounted uponcertain of such forms torenderv them moreread ilyandsafetyoperated;"'especially when a' load carried'b y the jack is inprocess of being lowered.

In the describedfiguresAdenotes the frame; base, or standard of a jack,and B the ratchet bar-:common to this particu r type, sidebar beingguided'slida'bly in'a vertical direction'with' 8 Claims. (Cl. 254-1 1;)all} mecha in a chann'ei C'of'saidframe or base, the ratchet teethfDinthis instance being exposed above the said'frame for pawl engagement, aswell as at a recess 'E in such frame also for pawl engage-j mer t.Also,'extendingfrom the frame forward- 1y jatjeach sideoftheratchet barBisa lug or car t 'E si e .2 h ii mw su o t l y; by a 'bo lt G theforked end off a hand l'eVer J. Asparts "oi said forked end isa pair ofarms K,

each ,bei r ig spaced outwardly from each exten-' sion o-f-thegfork;both said extensions and'sa'idarms may be substantially coextensive inlength.

Pivotally hung from between each lever-extensionanditsadjacent arm is anarm of a liftingpawl glhaving the usual forrnof a U whose depending yokeportion is adapted for engaging a toothof the said ratchet-bar withinthe recess E. Againa load supporting pawl M is mounted to swing on thenamed bolt G in position to engage the teeth of the ratchet-bar, aspring N secured at one end to the frame and having a position to bearatits other end on thejpawl "to urge the same 'in the. direction of Said rSuch a structure is more. or less common'to jacks and has merely beenoutlined for the purses of; a d n he u er ta h an: ner placingandjmounting of the combined nism as an" operating whole. p o Thepartsincludedin theinvention toicooperate "with'pajrts of the abovedescribed structure.

ally connected inan'y desired manner to the pawl I M is onegendvoff arod I which extends at'its other endalongsthe hand lever. J ,therebeing, in this, instanca a helically wound spring 2 slidable alongjthered, the "latter terminating in abutment L r Aflixedlto the hand leverdistant from the pawl M alm m e'r hav n t h #1 1 it op providing a'fork, wherein the rod may lie and" withim vhich also, said rod mayfreely shift in thelrai'sin'g and lowering movements of said handle K s0 Suitably afiixed"'to one or the, arms ofthede scribed lifting pawl-L,near its place of pivotal suspension, in finger 5 which, in thepres'ent' instance, extends upwardly and forwardly from a na\v ,..s idfin r 15, in a "Pa Of .ih

pawLfhaying a certain oflice' to be made known;

Fina11y,'pivoted' on the hand lever near the pivotal mounting of that.membe'rfisi a V tubular stem 6," shown best Figures 4 and'5."

While all this structure described as applied I to the jack parts answerthe purpose for which they are intended it is, of course, possible tootherwise construct them to at thesame time answer the said purpose. I

In the position of the new structural parts shown in Figure 1 the jackin operation answers for lifting purposes as inany jack of a like type,there beingnocontrolof the weight holding pawl M-nor controlof thelifting pawl L by said new structure, the only control being the usualspring N forsaid pawl M, and the force of gravity for the said lifting.pawl L. That these pawls may be free to function normally in liftingoperations, the stem 6 is in a forward or neutral position where in theoperation of the hand lever it will not move into the vicinity of norhave contact with the finger 5. Likewise in Figure 1 the rod 1 is freeto slide within the member 4 the-spring 2 having no office in theposition shown since in an inoperative position clear of any partWhen,.however, a sustained load is to be lowered and the hand lever isin a raised position, or even in the positionsshown in Figures 1 and 6,the rod I .may be lifted free of the member 4. Then by shifting thespring 2 along said rod one .end may lie against the abutment 3 whiletheother end may be made to abut member 4 when the rod is replaced inthat member.

:At the time the lever is lowered the spring will be compressed as themember 4 moves further away .from the pawl. Thus the spring serves towithdraw the pawl M from tooth engagement.

.Also, the stem 6 is swung from the position shown in Figure .1 towardand beneath the finger 5 of the lifting pawl I to engage the same as theleverrises.

.Having performed these acts the action of the jack is as follows:

When the lever is lifted the pawl M is allowed to move intotooth-engagement due to the movement of the rod l toward the ratchetbar, the spring N of that pawl now taking control, said pawl now, .ofcourse, engaging a tooth to support the load. In the said lift of thelever, also, the pin 1 is moved up to and abuts the under surface of thefinger 5. In the continued upward lever movement the-spring 8 beneaththe said pin 1 is compressed from the fact that the pawl L, of which the.finger is a part, is momentarily fixed and held in supporting the load.A completion of lever movement relieves the weight on said pa-WJL, the.pawl Mnow holding the load, whereuponthe reflexaction of said spring 2swings said pawl. L clear of the ratchet bar. Since gravity now controlsthe .pawl L, that member after its release, will drop into engagementwith a ratchet barv tooth in a succeeding upward movement of the handlever.

In lowering of the hand lever the pawl M is withdrawn from .a tooth.as'before .noted and .is held away from the ratchet bar by said rod 1and its spring 2, the pawl L which is in engagement with a toothnaturally being raised due to its connection with the lever at theforked end thereof.

It is now believed to be clear that the described structure involved inthis invention automatically and positively controls both pawls L and Min the lowering of the ratchet bar, the pawl L being withdrawn forengagement while the pawl M is in engagement. Also that when the latteris disengaged-the former is engaged. Thereby the operator is free tomanipulate the hand lever without giving manual attention as heretoforerequired in respect to said pawls in a jack of the type consideredherein.

.Isclaim:

1. In a liftingiack including a base portion, a ratchet bar, a gravityoperated lifting pawl, a spring operated holding pawl, and a hand lever,in combination, a rod operatively connected to the spring operatedholding pawl and provided with an abutment. a part carried by the handlever to swing about the lever-fulcrum to slidably receive the-rod, aspring on said rod adapted tolie between the abutment and said part andabutting both, the lowering movement of said lever adapted through saidspring to withdraw said pawl from engagement with the ratchet bar, andin the raised positionof said lever said pawl being free to engage saidratchet bar, an extension havinga, fixed position on the lifting pawl, apart mounted on the hand lever adapted to be moved to two differentpositions thereon, said part in one position lying adjacent theextension and lying distant therefrom in the other position, and saidpart when in the first named position adapted in a lifting movement ofthe hand lever to abut said extension and move thesame to swing saidlifting pawl away from the ratchet bar.

2. In a lifting jack including a base portion, a ratchet bar, a gravityoperated lifting pawl, a spring operated holdingpawl, and a hand lever,in combination, a rod operatively connected to the spring operatedholding pawl and provided with an abutment, a part carried by the handlever to swing about the lever-fulcrum, a part on said lever to slidablyreceive the rod, a spring on said rod and engageable with the saidabutment and said part adapted in the lowering movement of said lever towithdraw said pawl free from engagement with the ratchet bar, theraising movement of the said lever releasing the tension of said springto allow said pawl to engage said ratchet bar, an extension having afixed position on the lifting pawl, a part mounted on the hand leveradapted to be moved to two different positions thereon, said part in oneposition lying adjacent the extension and lying distant therefrom in theother position, and said part when in the first named position adaptedin a lifting movement of "the hand lever to elastically abut saidextension and move the same to swing said lifting pawl away from theratchet bar.

3. In a lifting jack including a base portion, a ratchet bar, a gravityoperated lifting pawl, a spring operated holding pawl, and a hand lever,in combination, a rod operatively connected to the spring operatedholding pawl and having an abutment, a part carried by the hand lever toswing about the lever-fulcrum, .a part on the lever with'which the rodis engage'able, a spring arranged to have two different positions on therod, and in'on'e position lying between'the abut-j .5 inent and saidpart, and adapted in the lowering movement of said lever to assist inwithdrawing said pawl from engagement with the ratchet bar, and in theraised position of said lever said pawl being free to engage saidratchet bar, an extension having a fixed position on the lifting pawl, apart mounted on the hand lever adapted to be moved to two differentpositions thereon, an elastically controlled pin carried by the part,said part in one position lying adjacent the extension and lying distanttherefrom in the other position, and said pin in said part when in thefirst named position adapted in a lifting movement of the hand lever toabut said extension and move the same to swing said lifting pawl awayfrom the ratchet bar.

4. In a lifting jack, the combination with the base portion thereof, aratchet bar, a gravity operated lifting pawl, a spring actuated holdingpawl, and a hand lever controlling said lifting pawl, of a rod pivotallyconnected to the holding pawl and including an abutment, a partcarholding pawl and extending along the hand lever toward its free end,said rod having an abutment remote from said pawl, a part fixed on thelever at a position between said pawl and the said abutment, a member onthe rod insertable between the said part and said abutment to provide anelastic control of the pawl in a movement of the hand lever in onedirection, said member being normally free of the said part and saidabutment, an extension on the lifting pawl fixed with respect theretoand lying at that side of the pivot thereof most distant from the partthat engages the ratchet bar, a stem pivoted on the lever adapted toswing and in one of its positions lying beneath said extension, saidstem having a part to elastically abut said extension in the liftingmovement of a said lever, the elastically abutting part adapted ried bythe hand lever at a position thereon between its fulcrum and itsoperated end, a spring engageable with both the said abutment and saidpart adapted by compression thereof in the lowering movement of thelever to bring about the withdrawal of said holding pawl from theratchet bar, said spring being disengageable from the abutment and partat another period in the movement of the lever, an extension fixed withrespect to the said lifting pawl, a second part on the hand leveradapted to swing toward and from said extension, a portion carried bythe said second part adapted to elastically engage the said extensionwhen said part is adjacent the same, said portion acting to swing thesaid lifting pawl away from the ratchet bar when the said hand lever israised.

5. In a lifting jack, the combination with the base portion thereof, aratchet bar, a gravity operated lifting pawl, a spring actuated holdingpawl, and a hand lever controlling said lifting pawl, of a rodoperatively connected to said holding pawl and including an abutment, apart carried on the hand lever with which said rod may be at timesoperatively controlled, a spring on said rod to be selectively placedbetween the abutment and the said part or removed from both, and when inthe first named position assisting in swinging said holding pawl awayfrom the ratchet bar in opposition to the spring of said pawl during themovement of said lever, a part pivotally mounted on the lever adapted tobe manually swung toward and away from the lifting pawl, and anextension on the latter in position to receive the part elasticallyagainst it to swing said lifting pawl away from said ratchet bar. 7

6. In a lifting jack, the combination with the base portion thereof, aratchet bar, a gravity opto swing the lifting pawl free of the ratchetbar when said pawl is relieved of weight thereon.

7. In a lifting jack, the combination with the base portion thereof, aratchet bar, a gravity operated lifting pawl, a spring actuated. holdingpawl, and a hand lever controlling said lifting pawl, of a rod connectedto said holding pawl, a part carried on the hand lever with which therod may be operatively connected to selectively swing said holding pawlaway from the ratchet bar in opposition to the spring of said pawl, anextension on the lifting pawl which when raised will swing said pawlaway from the ratchet bar, and a part on the lever normally spaced fromsaid extension, said part adapted when moved beneath the latter toelastically engage and lift it in a lifting movement of said lever.

8. In a lifting jack, the combination with its base and ratchet bar, agravity operated lifting pawl, a holding pawl, and a hand lever, of arod pivotally connected to the holding pawl and including an abutment, aforked part carried by the hand lever wherein the rod may lie butli-ftable therefrom, a coil spring shiftable along the rod adapted inone position to lie between the said abutment and the said part duringthe lowering movement of the ratchet bar, and in another positionthereof removed from between said abutment and said part during theraising movementpf the ratchet bar, an extension on the lifting pawlwhich when raised will swing said pawl away from the ratchet bar, and apart on the lever normally spaced from said extension, said part adaptedwhen moved beneath the latter by said lever to elastically engage andlift it in the lifting action of said lever.

FRANK P. HALLOR.

file of this patent:

erated lifting pawl, a spring actuated holding pawl, and a hand leverpivotally carrying said lifting pawl, of a rod pivotally connected tothe UNITED STATES PATENTS Number Name Date 655,705 Gallagher Aug. 14,1900

